The flexible, ultra-thin, and transparent electronics of the future places new dimensional, functional and performance demands on materials properties. Current semiconductor fabrication strategies based on bulk semiconductor materials encounter severe challenges in meeting such goals. The discovery of graphene, followed by the rise of other two dimensional (2D) materials in the past decade, has not only extended scientific understanding of atomically layered structures, but has also enabled a straightforward path to future unconventional electronics. This has led to the realization of atomically layered field effect transistors (FET), photodetectors, photovoltaics, nonvolatile memories, optoelectronic memory for gate tunable photodetector, and optical switcher which were further integrated with polymeric substrates to demonstrate prototypes of flexible electronics. However, an optoelectronic memory for image sensing, an essential part in modern electronic devices, that utilizes 2D atomic layered materials has not been demonstrated.
Image sensing places special requirement on optoelectronic sensors. It should reflect exposure dose instead of exposure intensity. The output of sensor should be history-dependent to realize complicated image processing functions, such as image integral, weak signal accumulation, etc. Ordinary photodetector cannot fulfill these requirements, whereas optoelectronic memories, such as charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) device, are commonly utilized and play essential roles in image capture, spectrum analysis, bio-sensing, etc. These optoelectronic memories can accumulate the photogenerated charge carries during exposure, and release the stored charge for information retrieval.
A 2D atomically layered material based optoelectronic memory can broaden the realm of optoelectronic memories, and it can be easily integrated with other 2D material based devices, such as FET and nonvolatile memories, as well as provides the possibility for construction of a large-scaled, whole 2D material based, complicated functional unit.